Go to the Cub site linked above and click on "Illustrated Parts Look-up Tool". Then enter "1641" in the "Model Name/Number" search box in the upper left of the screen. Then select which serial number range your tractor falls within, then on the right side of the screen click on "Illustrated Parts List", then "Attachments" to see what was available for your tractor.
The fact that there was a 54" blade and 3-point hitch means your tractor is a beast. I wouldn't worry about plowing snow. You'll lose traction LONG before you even begin to stress it.